Why does only the hot water smell like sulfur?
Hot water heaters develop a sulfur or rotten egg smell when sulfate-reducing bacteria react with magnesium anode rods inside the tank. This makes the water unpleasant to use and often leads tenants and homeowners to mistakenly believe the well water itself needs cleaning.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
- 1Flushing and cleaning the tank
- 2Replacing the anode rod with a different material
- 3replaced the anode with a Corro-Protect
- 4trying to drain the water heater
- 5testing the water on hot and cold taps
In their words
Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.
r/Plumbing2 people · September 2026 – October 2026
Where this came up
People with this problem also raised
- 2Air coming out of hot water lines only
- 2Strong gas smell in room after new pipe installation
- 2Why is there a raw fuel smell and rough idle when stopped?
- 3Why does only the hot water smell like sulfur after moving in?
- 3Why does my water heater closet smell bad?
- 4Why does it take so long for hot water to reach distant bathrooms?